Chain cutter for sewing machines



F. LUTZ May 26, 1931.

CHAIN CUTTER FOR SEWING MACHINES Filed Jan. 10, 1929 Patented May 26, 1931 UNITED STATES PATENT; 'DFFICE rmnonrcn .LUIZ, or 'sru'rremr, GERMANY,- assrenon r umon srncun auecmmrnarx, e. m. B. 3., or sru'r'reaar, enmity ting 0mm corms. roa smwme MACHINES Application filed January 10, 1929, Serial No. 331,441, and, in Germany came: 1c, 1928.

The invention relates to new and useful improvements 1n chain cutters for sewing ma chines and more particularly to a chain cute ter which is operated automatically for cutthe enchained thread loops between stitched articles.

An object of the invention is to rovide a chain cutting mechanism wherein t e severing devices are power operated for severing the chain, and wherein means is provided controlled by thefabric bein stitched independent of the presser foot or causing the power mechanism to be connected to the severing devices after the stitched article moves from beneath the presser foot for severing the enchained thread loops.

In the drawings:

Fig. 1 is a view showing more or less dia-V grammatically the improved chain severing mechanism as applied to a sewing machine.

Fig. 2 is a sectlonal view on the line 2-2 of Fig. 1 showing the trimming lever and the control lever in plan.

Fig. 3 is a side view-of the control finger which brings about a connection of the severing devices to the power actuating means.

In my copending application, Serial No. 316,434, filed November 1, 1928, I have disclosed a chain cutter for sewing machines wherein the chain severing devices are automatically connected to a power actuating mechanism by means controlled by the raising and lowering of the presser foot so that when an article being stitched passes from beneath the presser foot, the chain severing devices will be connected to said power actuating means and the chain severed. The present invention is directed to a chain severing device of a similar character wherein the control for coupling the movable severing device to the power actuating member is 1ndependent of the presser foot and through direct connection I with the article being stitched. I

By this arrangement, one article after another may be passed beneath the presser foot for stitching without the presser foot passing of from the first article onto the cloth plate and then being raised by the next article in order to bring about an actuation of the presser bars indicated at 2,3. One presser foot is indicated at 4: and the cloth plate on which the fabric rests at 5. These parts are all of the usual construction and detailed 'de- I scription thereof is not necessary.

Mounted on the cloth plate so that its cutting face is substantially flush therewith is 'a stationary trimming blade 6. Cooperating with this stationary trimmin blade is a movable blade 7. In Fig. 1 oft e drawings the view is taken from the rear of the machine,

and it will be noted that these trimming devices are arranged so as to operate in a plane at right angles to the line of feed for cutting the enchained thread. loops between stitched articles. The movable trimming blade 7 is carried by an arm 8. lhis arm is rigidly connected to a shaft 9. Rigid with the arm 8 is another arm 10. These two arms move as one with the shaft 9. The shaft 9 is mounted on a yoke bracket 11 which is fixed to the overhanging arm 12 of the machine. Pivotally connected to the upper end of the arm 10 is a latch or clutch member 13. Said clutch member is pivoted at 14 to said arm. A spring 15 secured to the arm 10 by means of suitable screws bears on the tapered rear end of the clutch member 13 and normally turns said clutch member on its pivotal support in a clockwise direction. A stop screw 16 carried by the clutch member engages a shoulder 17 on the arm 10 and limits the clockwise movement of the clutch member.

A spring 18 coiled about a sleeve on the shaft 9 is secured at one end to the yoke bracket 11 and at its other end to the arm 8 carrying the movable trimming blade. This spring normally tends to raise the trimming blade from its operative relation to the stationary trimming blade 6.

Mounted on the overhanging arm is an actuating lever 19. Said lever is ivoted at 20 to the overhanging arm. This ever is continuously oscillatedb means of a link'21 which is in-turn actuate by a suitable con nection with some moving part of the sewing machine. Mounted in the lower end of the lever 19 is a clutch member 22. Said clutch member is mounted in a socket or recess in the lower end of the lever and is held therein by screws 23, 23. The clutch member 22 is provided with an upturned end forming a shoulder 24. The clutch member 13 is provided with a knife edge 25. When the arm 10 is moved to a sufficient distance in a clockwise direction, the clutch member 13 will be so positioned relative to the clutch member 22 that the knife ed e 25 will drop behind the shoulder 24. and t e two clutch members will thus be joined together. WVhen so connected the oscillations of the lever 19 will impart oscillations to the arm 10 which in turn oscillates the arm 8 and this will move the cuttin blade 7 relative to the stationary blade 6 or cutting the enchained thread loops. This clutching of the movable cutting member to a power actuatin device is shown and claimed in my copending application above referred to.

The present invention is directed particularly to the manner in which the connecting of the clutchin .members together and the disconnecting 0 said clutching members is accomplished. Mounted on the shaft 9 is a yoke member 26, which yoke member carries a control arm '27. Secured to this control arm 27 is a control finger 28. This control finger is provided with an inclined portion 29 and a foot portion 30. The foot portion 30 lies substantially beneath the arm 8 carrying the movable cutting blade 7. A spring 31 is coiled about a sleeve on the shaft 9 and one end of this s ring is connected to the yoke bracket 11, w ile the other end is connected to the yoke member 26 carrying the control arm.

The control arm 27 extends upwardly from the yoke member as shown in Fi 1 and thence laterally. Extending throng the upwardly extending portion of the arm is an adjustable screw 32. The spring 31 is of greater tension than the spring 18. The spring731 normally tends to move the control arm 2 in a clockwise direction which is contrary to the direction of movement of the arm 8 by the spring 18. When the arm 27 is permitted to turn in a clockwise direction the adjustable screw 32 engages the arm 10 and will turn said arm in a clockwise direction. This will lower the movable trimming blade into cooperative relation to the stationary trimming blade. The fabric being stitched is indicated in broken lines at F. The fabric is beneath the presser foot in Fig. 1 and the presser foot is raised. At this time the foot 30 of the control finger rests on to of the fabric and thus it is that the contro arm 27 is raised.

When this control arm is raised then the screw 32 is moved out of contact with the arm 10 and the spring 18 raises the movable cutting blade 7 to its inoperative position. This movement of the arm 10 brings the shoulder 17 into contact with the stop screw 16 and will cause the knife edge 25 to be disconnected from the shoulder 24.

When the fabric F passes from beneath the presser foot even though another fabric section immediately follows so that the foot does not lower from the position shown in Fig. 1 the control finger will drop until it makes contact with the cloth plate. As it drops to this position through the action of the spring 31 then it is that the screw 32 engages the arm 10 and lowers the cutting blade 7 to cooperative relation with the stationary blade 6. This turning of thearm 10 in a clockwise direction will causethe clutch member 13 to move so as to come into engagement with the clutch member 22 and the movable cutting blade will be actuated through the connection with the power mechanism for severing the enchained thread loops. This actuation of the chain severing devices will continue until the control finger is raised. The control finger is raised by the fabric F passing underneath the same as shown in Fig. 3.

It will be apparent from the above description that I have provided a chain severing device for cutting the enchained thread loops between stitched articles which is power actuated and which is automatically controlled so that regardless of the position of the presser foot the movable chain severing device will be connected to the power actuating mechanism and operated to sever the enchained thread loops between stitched articles which are comparatively close together. Only sufficient space is necessary between the articles to allow the control finger to dro into contact with the cloth plate for a su ficient length of time to bring about a lowering of the movable cutting blade and a connection of the means which supports it to the actuating devices therefor.

It will be obvious that minor changes in the details of construction and the arrangement of the parts may be made without departing from the spirit of the invention as set forth in the appended claims.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In a sewing machine, a presser foot, a feeding mechanism, a stitch forming mechanism in luding a needle, and chain cutting devices located in rear of the needle and including a cutting blade, an oscillating member supporting said cutting blade, actuating means for said cutting blade, a member mounted for oscillation about the same axis as the cutting blade and adapted to contact with the material passing under the presser foot, and means controlled by said member for connecting and disconnecting the cutting blade with its actuating mechanism.

2. In a sewing machine a presser foot, a cloth plate, a stationary cutting blade carried by the cloth plate, a rock lever, a movable cutting blade carried by said rock lever, a spring normally turning said rock lever to raise the movable cutting blade to inoperative position, a power actuating device, a clutch mechanism automatically connecting said actuating device to said rock lever when said movable blade is moved into operative relation to the stationary blade, a control arm having a control finger adapted to be raised by the article being stitched, a spring for normally moving said control finger into engagement with the article being stitched, an adjustable stop member onsaid control arm adapted to engage the rock lever, said spring operating the control arm being of greater tension than the spring operating the rock lever whereby when said article passes from beneath said control finger said control arm will move the rock lever bringing said movable cutting blade into coo erative relation with the stationary cutting lade.

In testimony whereof, I aflix my signature.

FRIEDRICH LUTZ. 

